Perfluoroalkanesulfonylphenol compounds are useful as production intermediates of pharmaceuticals and agrochemicals (see WO2014/104407).
For the production thereof, a method of producing a perfluoroalkanesulfanylphenol compound from a phenol compound and then oxidizing the perfluoroalkanesulfanylphenol compound is commonly used (see WO2014/104407 and Journal of Organic Chemistry, 1964, vol. 29, p. 898 to 900).